Means for atomizing and igniting liquid fuel



A. DOBLE.

MEANS FOR ATOMIZING AND |GN|T|NG LIQUID FUEL.

APPLICATION FILED FEB. 28, 1918.

Patented Dec. 6, 1921.

2 SHEETS-SHEET l.

A. DOBLE..

MEANS FOR ATOMIZING AND IGNITING. LIQUID FUEL.

APPLICATION FILED FEB. 28., F918.

Patented Dec. 6, 1921.

2 SHEETS-SHEET 2.

(gm/www1 Z,

` eren stares l msnm DOBLE, or DETROIT, MICHIGAN.

MEANS ron A'roNIzI'Ne AND IGNITING LIQUID rum..

Specication of Letters IIatent.

'iIPatented Dec. 6, 9211.,

Application tiled February 28, 1918. Serial No. 219,671.

To all/whom 1f/may concern: .i

Be it known that I, ABNER DoBIlE, a citizen of the United States ofAmerica, and resident of Detroit, Wayne county, \Michi an, have inventeda certain new and useful lmprovement in Means for Atomizing and IgnitingLiquid Fuel, of which the followin is a specification..

y invention relates to the art of burning heavy hydrocarbons which arenon-volatile or substantially so at normal temperatures, and myinvention comprises a means of instan'taneous ignition or initiation ofcombustion of such hydrocarbons in their normal tem erature condition.

invention has its application inconnectlon wtih the Iutilization ofheavy hydrocarbons, such as kerosene and distillate, as fuel for therapid generation of steam in the power-plant of steam-drivenautomobiles, wherein the elimination of the annoyance and delay of.pre-vaporization of the fuel and the rapid generation of steam areessential requisltes in a commercially successful automobile. v l

Heavy liquid hydrocarbons suchv as/kerosene can, as I have found inpractice, be veryv eH'ectively and completely burned, withoutpre-heating or pre-vaporization, from an initially normal or so-calledcold temperature condition and extremely high temperatures obtained forthe generation of steam, by the atomization process of finely dividingthe liquid and mixing it with the proper amount of air to supportcombustion and confining the combustion in a closed refractory chamberwhich attains an intense heat.

'.lhehydrocarbon at normal temperatures may be atomized Aor broken upand mixed with the proper proportion of air to com- .plete `combustionwithin said chamber, or the air which supports combustion may be used asthe atomizing ,agency for finely dividing the hydrocarbon and projectingit into the combustion chamber. ln any event, however, there must be asufficient proportion of air in the mixture to complete combustion inthe combustion chamber, without anysmoke or soot whatever, else the veryadvantage attendant upon a utilization of the atomizing method in asteam-driven automobile ower-plant is lost. As before mentioned,

have found in practice that a mixture of the atomized fuel and airburned in a cham-l ber in the manner above mentioned can be completelyconsumed without soot and smoke, but such a mixture (which I will referto, for convenience, as the main or completely combustible mixture), hasa relatlvely excessive proportion of air and a relatively smallproportion of atomized fuel. In

other words, relatively speaking, this mixture is rich in air and leanin hydrocarbon.

The extreme desirability in an automobile power-plant of instantaneousinitiation of combustion of fuel and the use of an electric spark forthis purpose, is at once obvious, but a mixture such as I have justdescribed will not ignite at normal temperature by means of an electricspark, although after aving been properly ignited, it will sustaincontinuous combustion in said chamber. So far as l am able to ascertain,the failure of this mixture to ignite from a spark is due to the factthat a spark of lpractical proportions, although intensely hot, iscomparatively small in volume, and in such a relatively lean mixture theparticles of fuel are separated in a comparatively large volume of airto suchv an extent that the air absorbs the heat and prevents thetransmission of heat to adjacent particles. from those i nited.Furthermore, if in addition the bo y of mixture is moving atcomparatively high A velocity, the particles do not remain in the smallzone 0f flame of the spark long enough to become ignited.

l have discovered, however, that a mixture of iinely dividedvhydrocarbon and air at the normal atmospheric temperatures can readilybe instantly ignited by an electric spark` if the mixture is excessiveor rich in hydrocarbon and lean in air and thoroughly atomized to form adense fog or cloud, but, on the other hand, a mixture of this characteris not completely'combustible, there being insuiiicient air therein toentirely o-r completely consume the hydrocarbon which is so greatly inexcess of the air supplied even under the most favorable conditions,hence such a mixture (which, for convenience of reference, l will termthe auxiliary or .incompletely combustible mixture) is not adapted forcontinuous combustion purposes because it burns incompletely, isproductive of smoke and soot, disagreeable odor and would not developthe necessary temperature if used in van automobile power-plant. Asbefore mentioned, however, this mixture will readily and repeatedlyignite by an electric spark because, so far as I- am able to ascertain,the .particles of hydrocarbon are relatively close together and notdiluted with air toany great extent; hence the heat generated by thespark, although small in without pre-vaporization, the instantaneousignition of a completely combustible mixture at normal temperature forthe sustained or continued production of heat by means of an electricspark, which result, in the case of an automobile power-plant, leavesnothing for the operator to do butto start the sparking and mixtureforming mechanisms, and

-which in practice amounts to nothing more than the operation of anelectric switch.

I accomplish these result-s by producing a main mixture of finelydivided liquid normally non-volatile hydrocarbon and air in suiiicientproportions to completely burn this hydrocarbon, and a secondincompletely combustible or auxiliary mixture of smaller volume, thesecond mixture being arranged in igniting relation to said main mixture,and in the zone of the auxiliary mixture I introduce an electric spark.The heat of the spark ignites the auxiliary mixture which transmits itsflames to and ignites the main mixture. The flame of the auxiliarymixture need be maintained only for a sufficient period of time to bringabout the ignition of the main fiame.

The object of my present invention is to provide an improvedmixture-forming and ignition mechanism for automobile powerplants, whichmechanism will produce a combustible liquid fuel mixture and willinstantaneously ignite or initiate combustion in said mixture at normaltemperature.

Other objects of my invention will appear hereinafter.'

The accompanying drawings illustrate an automobile power-plant structurewhich embodies my invention and which accomplishes the desired results.r

In the drawings:-

Figure 1 is a sectional view through the blower, a portion of thecombustion chamber, and one of the atomizers of the fuelspraying,mixture-forming and ignition mechanism embodying my invention;

Fig. 2 is a transverse sectional view of the structure shown in Fig. 1,taken substantially on the line 2-2 of Fig. 1;

Fig. 3 is an enlarged detail section of the fuel nozzles for producingthe different mixtures of fuel and air;

Fig. 4 is a view in diagram illustrating my improved structure andcontrol system4 therefor, as arranged for use-in a steam drivenautomobile power-plant. l

. The structure shown in the drawings involves a blower 10 of anysuitable type capable of supplying large volume of air at'comparativelyloW pressure for the purpose of atomizing or breaking upthe liquid fuel and forming therewith the completely combustible or mainmixture to which I have referred. This blower has a fan or blade wheel11 rotating within a casing 124 and driven by means of an electric motor13 mounted on the blower casing. The blower has its outlet 14'dividedinto two sectionsjl extending horizontally and in parallel relation andthe ends of these sections .are removably fastened to the wall 16 of theinclosure within which is positioned the fire-pot 16a forming thecombustion chamber. The

combustion chamber is shown in position beneath a steam generator 16b ofan automobile power-plant, this chamber being arranged to lnclose thelower end of the generator casing 4so that the heated products ofcombustion will rise directly in said generator. The end portions of theblower outlet sections are tubular and contain removable Venturi tubesor members 17, and within the combustion chamber there 1s provided acasting 18 having two tapered passages 19 which are alinecl with andform continuations of the Venturi tubes, to direct the s'prays of fuelmixture into the combustion chamber. The Venturi tubes are of coursetapered to a restricted throat portion 171so as to increase the velocityofthe air passing therethrough and at these throat portions are fuelnozzles which supply the fuel to be atomized. These fuel nozzles areformed by the small Venturi tubes 2O mounted upon upstanding posts 21 ona common manifold member 22. The A fuel is admitted to these taperedpassages through the openings 23 in the upper sides, these openingscommunicating with the annular passages 24 formed by grooves on theouter surface of the nozzle tubes. The upper ends of the posts haverings which support the nozzle tubes and close the annular passages, andthese posts also have passages 25 which convey the fuel from themanifold passage 26 to the nozzles. At one end of the manifold, I mounta float chamber 27 which may be of any suitable type, for the purpose ofmaintaining the liquid fuel at the proper level in the fuel nozzles. Theliquid fuel is carried in a suitable tank 29, which in practiceismounted on the automobile frame at a point somewhat below the fuelnozzles, and, in order to raise the fuel to the float chamber throughthe feed pipe 30, I provide air pressure of a few pounds in the tank.

This pressure is supplied b 'a hand-pum 31 connected by pipe 32 wi thefuel tan above the level of the oil..4 The blower, as before mentioned,provides a constant blast or current of air. through each ofthe Venturiassages, and, in accordance with the principles of atomization, drawsthe liquid fuel froxnthe nozzles and finely divides it, a portion ofthecurrent of air being diverted through the small nozzle passages toassist in breaking up the fuel, thus producing sprays of fuel from thenozzles, which at the ends of the nozzle tubes is mixed with greatvolumes of air. This action produces a mixture of fuel and air in suchproportions as to support complete combustion in the fire-pot. A dilutemixture of this character wherein there is a proper proportion of air tosupport complete combustion will burn without soot, smoke or odor, andwill supply the volume of heat necessary for the rapid generation ofsteam, and can be easily controlled after having been ignited, but sucha mixture is entirely incapable of being ignited at normal temperatureby the small liame of. an electric spark or equivalent ignition means ofpractical proportions and of instantaneous operation. I thereforearrange the structure so that it will also produce a diferent mixture offuel and air which is capable of ignition by an electric spark, and thellame of this spark-ignitible mixture is utilized for the ignition ofthe main combustible mixture. l'. accomplish this by the provision ofsupplemental nozzles 34 which are positioned to direct a small volume ofhigh pressure air in the form of a fine jet into the main nozzles,thereby aspirating a sufiicient'increase in the amount of liquid fuel tobe atomized, to enrich or superimpose upon the main mixture at the mainnozzles a properly atomized dense fog or rich mixture which is capableof instantaneous ignition by an electric spark or its equivalent.

For the purpose of conveniently obtaining suiiicient pressure for theair -jets,l utilize the compressed air in the fuel tank. Under theseconditions, the sprays of fuel mixture at the main nozzles are of suchproportion that they will readily ignite from a cold condition by aspark, and the ames from the burning sprays will instantly i nite themixture produced by the blower air and main nozzles. The spark forignition purposes takes place between the electrodes 35 and 36, justwithin the ends of the main nozzle tube passages. rlhe electrodes 35 areformed by projections in the main nozzles which are suitably grounded at37, while the other electrodes 36 are carried by spark plugs 38, screwedinto the Venturi tube members and connected to the secondary winding 39of a suitable spark coil by means of the conductors 40..

`The mixture which is thus produced and which is capable of sparkignition, however, is incompletely combustible and can- `relativelysmall as compared with the main sprays, and, if not continued too long,its smoke and soot will be consumed in the combustion chamber. As amatter of practice, the duration of the ignition mixture need be butmomentary, because the matter of time from the initiation of the sparkuntil the main sprays become ignited ispractically instantaneous. Forthese reasons, it is advisable to maintain the ignition mixture forveryshort periods of time when required to ignite the main mixtures, andinl Fig. 4 I illustrate a controlling systemwhich`automatically'determines the period of duration of the ignition flameand spark igniter. The controlling mechanism involves an air storagereservoir 44 capable of holding a charge of air under' pressuresufficient to operate the air jets for the proper period of time. Thisreservoir is illustrated as larger than the fuel tank for the sake ofclearness of illustration, but it will be understood that in practice itis smaller and of considerably less capacity than the fuel tank, thefuel tank being capable of holding suflicient compressed air to chargethe reservoir many times. The reservoir has a passage 45 connected bypipe 46 with the compressed air supply in the fuel tank, and thispassage is controlled by a valve 47 at one end of the valve stem 48.This valve is maintained normally open to keep the reservoir suppliedwith air by means of the spring 49. A pipe 50 leads from the reservoirto the air jets 34, and the reservoir outlet is controlled by a valve 51on the lower end of the valve stem 48, this valve being normallyclosedby the spring 49.V When the lower valve is opened and the upper valveclosed, the charge of air in' the reservoir will operate the atomizer 34until the charge of air is dissipated, whereupon the high pressure airwill be cut off from these air jets. rl'Che valve stem is operated by asolenoid 55 which is `controlled by an operators switch 56. The currentfor this ma net is supplied from a grounded battery 5%, over the circuitconductors 58, 59 and 60 to ground.' The valve stem also carries aswitch member 61 which closes the motor circuit 62 through the contacts63, so that, when the operator closes nism and blower will b e startedsimultaneously. In the event that the air pressure in the reservoir 44or fuel tank 29 should fail and prevent the operation of theignitionmechanism, it is not advisable to startthe main atomizers and fill thecombustion chamber with fuel; hence a diaphragm the manual switch 56,the ignition mechaswitch 64 is provided which is subject to the airpressure in the reservoir 44 and which normally holds the circuit of thesolenoid closed at the contact 65. Of course, if no air pressure existsin the supply, the contact is held open and the operators switch has noeffect on the system. The circuit 66,

,which includes the primary winding 67 of the spark coil is alsocontrolled by a diaphragm switch 68 similar to the switch 64, so that,while pressure exists in the reservoir 44, the spark coil circuit isclosed, but, when the charge of air'has been exhausted, this circuit isopened and the spark discontinued simultaneously with the discontinuanceof the pressure air to the supplemental air nozzles 34. The controlsystem which I have herein described constitutes the subjectmatter of myco-pending application serial N o. 178,513, filed July 3, 1917.

I claim:

1. The combination of a main Venturi tube, an auxiliary venturiincluding a fuel nozzle, in said main venturi, a supplemental nozzlearranged to project a jet of high pressure air in said auxiliaryventuri, an ignition device for igniting the spray formed by saidsupplemental nozzle, means for supplying air under pressure to saidsupplemental nozzle, and an air blower for supplysure air into saidventuriat a point adjacent said fuel nozzle, means independent of saidair blower for supplying high pressure air to said supplemental airnozzle, and an igniting devi'celfor igniting the spray formed by saidsupplemental air nozzle.

3. The combination of a blower having a Venturi tube outlet, a liquidfuel nozzle positioned in said venturi in aspirating relation to the airproduced by said blower to form a completely combustile mixture, asupplemental nozzle for projecting an independent fuel nozzle tovproduce an incompletely combustible mixture, an ignitingV device forigniting said incompletely combustible mixture, and means formomentarily supplying pressure air to said supplemental nozzle.

`Signed by me at Detroit, Mich., this 25 day of Feb., 1918.

ABNER DOBLE.

stream of high pressure a1r into said liquid

